1. Field of Invention
The present invention relates to infrared surveys of geographical areas and, more particularly, to an improved survey system and method using infrared and color television images and having means for determining and recording coordinates of points of interest of the survey.
2. Description of the Prior Art
Geographical surveys utilizing infrared sensors are extremely useful for a number of activities. For example, such surveys are applicable to detection of gas pipeline links; detection of problems in electric power transmission lines; determining the density of populated areas; search and rescue missions; pollution studies; and timber surveys. Infrared detection systems provide information concerning areas having a distinct temperature differential from the background temperatures and use of such systems for surveys is known in the art. However, a major problem in such surveys that has not been adequately solved is accurate determination of the location of small ground features detected by an infrared system.
A typical prior art infrared survey system is disclosed by Dibbero, U.S. Pat. No. 3,076,961. An airborne multiple sensor system is used having an infrared camera, a television camera, and a radar scanner. The multiple sensors provide detection and identification of camouflaged targets such as required in military operations. No means for producing accurate ground coordinates of detected targets is provided. Parker et al., in U.S. Pat. No. 3,752,915, teach recording on magnetic tape of thermal ground and reference data obtained from an airborne scanner to produce color images. U.S. Pat. No. 4,516,158 to Grainge et al. shows two airborne infrared scanners that scan in different directions.
None of the above systems provide accurate identification of ground coordinates, such as latitude and longitude, of located targets nor altitude from which the survey was made. Therefore, a need remains for an accurate survey system utilizing infrared scanning, color video, and video recording that includes means for recording the latitudes and longitudes of small areas of interest located during the survey. For aerial surveys in which a system provides latitude and longitude coordinates, which provides means for locating the coordinates with a ground vehicle is required.